Compilare: main.cpp: In function 'int OK(int)': main.cpp:45:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<Q2.size();i++){ ~^~~~~~~~~~ main.cpp:61:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<Q.size();i++){ ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:86:23: warning: suggest parentheses around '+' inside '>>' [-Wparentheses] cin >> mat[i] + 1; ~~~~~~~^~~ main.cpp:81:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("barbar.in","r",stdin); ^ main.cpp:82:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("barbar.out","w",stdout); ^ main.cpp: In function 'int OK(int)': main.cpp:60:16: warning: 'sy' may be used uninitialized in this function [-Wmaybe-uninitialized] uz[sx][sy] = 0; ~~~~~~~~~~~^~~ main.cpp:60:16: warning: 'sx' may be used uninitialized in this function [-Wmaybe-uninitialized] main.cpp:76:21: warning: 'fy' may be used uninitialized in this function [-Wmaybe-uninitialized] return uz[fx][fy] != 1000000000; ~~~~~~~~~^ main.cpp:76:21: warning: 'fx' may be used uninitialized in this function [-Wmaybe-uninitialized]